Flat Dumbbell Fly: how to do it right
In short: Flat dumbbell fly: an isolation movement that loads the chest in the lengthened position, arms open in a cross.
How to do it, step by step
- 1Lie on the bench, feet on the floor, shoulder blades squeezed and pinned back, a slight natural lumbar arch.
- 2Dumbbells above the chest, palms facing each other, elbows bent at 15-20 degrees and fixed.
- 3Open the arms in a wide arc until you feel the pec stretch, hands at chest level.
- 4Brake this opening phase over 2 to 3 seconds, with no bounce or jerk at the bottom.
- 5Bring the dumbbells together imagining hugging a tree, contract the pecs without clanging them.
- 6Keep the elbow angle constant: don't close it to cheat into a press.
The mistake to avoid
Don't turn the fly into a press by bending your elbows.
Other common mistakes
- Elbows bending under the load: you turn the fly into a press, keep the angle fixed and lighten up if needed.
- Range too short at the bottom: you remove the key stretch, go down to the comfortable limit of the shoulder.
- Free-fall descent: without braking you lose the stimulus and load the joint, control it over 2 to 3 seconds.
- Lifting the shoulder blades off the bench: you lose your stable base, keep them squeezed and pinned the whole set.
Muscles worked
- Main:
- Chest
The pec major, middle (sternocostal) fibers, is the prime mover: it brings the arms toward the body's midline (horizontal adduction). The anterior delt and the pec minor take part as discreet stabilizers. Unlike the press, the triceps barely work here, since the elbow joint stays fixed.
What to replace it with
Same muscle, same part of the movement: these exercises do the same job.
- Dumbbell Floor Fly ›
- Dumbbell Bench Press ›
- Weighted Forward-Lean Dips ›
- Archer Push-Up on Handles ›
- Deficit Hands-Elevated Push-Up ›
Frequently asked questions
How do I do this exercise?
Lie on the bench, feet on the floor, shoulder blades squeezed and pinned back, a slight natural lumbar arch. Dumbbells above the chest, palms facing each other, elbows bent at 15-20 degrees and fixed. Open the arms in a wide arc until the pec stretches, then bring them together imagining hugging a tree. Never close the elbow to cheat into a press.
How low should I go?
Open the arms until you feel the pec stretch, hands at chest level. In the low position, arms open, tension is highest and that's where the stimulus happens. Don't rush through this point and don't bounce. Go for the range you control, not the one that forces your shoulder.
I don't feel anything, is that normal?
You should feel the stretch then the contraction in the pecs. On the fly, ego doesn't forgive: pick light and look for the deep stretch at the bottom rather than weight. A small half-second pause in the low position, under control, multiplies the stimulus. If you mostly feel your shoulder, lighten up and check that your elbows stay fixed.
How fast should I do the movement?
Brake the arm opening over 2 to 3 seconds, as the pec lengthens, with no bounce or jerk at the bottom. Then bring the dumbbells together crisply but in control. It's the braking at the stretch that does the work, not the speed of the return.
How do I breathe?
Inhale as you open the arms, when the muscle lengthens, to go with the expansion of the rib cage. Breathe out as you bring the dumbbells together, on the effort. Keep a light brace and the shoulder blades locked to protect the shoulder.